Such mixing devices are used in the manufacturing of multi component composite items. A known mixing device comprises mixing head with two non-return valves in separate inserts for closing and opening respective cavities or channels running to a mixing cavity. This mixing device is mounted to another appliance like a static mixer or the like where the mixed resin is further process.
The known mixing device faces a problem when cleaning is needed. Cleaning is either performed by filling in a cleaning shot thereby emptying the mixing device. The mixing device is flushed with the cleaning shot, the resin contained in the mixing device is spilled out of the device. Alternatively it is known to disconnect the mixing device from the following system before the curing of the resin takes place and to use a bucket or the like for spilling in the resin. Both alternatives bear problems. When using a cleaning shot it is not ascertained that all of the resin is completely flushed out of the mixing head. Especially in corners of the channels or the mixing cavity residual resin may remain. Demounting the mixing head is very cumbersome and somehow risky because the resin is still liquid and may spill out uncontrolled.